Influence on Configuration of Contact Support with Slits for Axial Magnetic Field Vacuum Interrupter

The axial magnetic field (AMF) vacuum interrupter (VI) with excellent current breaking performance even at long stroke require the contact support made of stainless steel (SUS) unlike other type of VI. The contact support prevents AMF contact from the high impact caused by closing operation of VI with long stroke. In our previous research, it was confirmed that the current breaking performance of AMF VI was influenced by the configuration of contact support. Accordingly, it is important to determine the configuration of contact support to develop VI with high voltage performance and large current breaking capacity. In this paper, the effect of number of slits and angle of slits in contact support was investigated on the current breaking performance of AMF VI. The current breaking performances i.e., maximum axial magnetic flux density at current peak (B
z
), effective area
$(\boldsymbol{\lambda})$
, maximum axial magnetic flux density at current zero (B
zo
) were derived by three-dimensional finite element method (3D-FEM). From the simulation results, it was confirmed that number of slits somewhat affects the current breaking performance although the influence was insignificant in case of more than four slits. On the other hand, angle of slits has no influence on the current breaking performance.